The first policeman on the scene of a crash which police tried to blame on a truck driver for using his mobile phone says there was never any suggestion the truckie was at fault.

Police earlier this month launched a series of YouTube clips promoting a road safety campaign, with one video blaming a truck driver for causing a high-speed crash.

They have since apologised to the people involved in the crash, but the road police officer first on the scene and who filed the evidence in court for the prosecution of a female car driver at fault said the truck driver was innocent.

"I was the lead officer and the first on the scene. Basically they have misrepresented the information they have been presented with. There was no suggestion right throughout the case of evidence of a cellphone," Matt Bourne said.

Mr Bourne, who is no longer a police officer, said he arrived at the scene of the motorway crash in Auckland and quickly worked out who was at fault.

The truck driver was breath-tested and passed, he said, and there was no mobile phone found in his cab.

Mr Bourne said it seemed someone "has seen the footage and thought, 'We can use this,' and fabricated something. I can't believe they've done that".

In the crash, which police sold in their YouTube advertisement as "Real CCTV footage of a truck driver who crashes while using his mobile", car driver Simon Cathcart was seen to flip at least six times after being struck from the side by another car.

Mr Cathcart said police had subsequently advised him the woman driving the other car was charged with careless driving causing injury, and pleaded guilty to the charge.